Replacing my 5.3L, what to look for?

I just posted another thread about dod and using a different ECM. I read about being able to disable dod with a tuner but just looking for any more info if this could be the cause. The motor came shipped to me complete with wiring harness, throttle body, injectors, coils, fan and motor etc.... They basically unplugged all connectors, removed alt, compressor, and front axle components and shipped it.
 
My original motor had a rod bearing go so living on a small island my only option was to find a replacement. Everything on old motor was fine except bearing was shot. Vehicle was running fine the day I pulled motor out minus obvious rod rattle so I have been using parts right off of it. Old motor only had 36000 miles on it and I bought from someone cheap knowing motor swap was in near future. So all parts are gm and identical to each I have replaced. The only thing I put on that's not gm is I bought an engine coolant sensor after breaking plug housing on the one from my old motor. I'm really starting to think this dod thing is coming on/off which is why it's coming and going???.... Frustrating though!!
 
is the sensor GM/AcDelco? In the 4.2 platform, PCM is sensitive to aftermarket sensors, sometime they work fine, other times they refuse to work.... Could be the same with the 5.3 ....
 
I'm going to take a boat ride over to gm dealer in stt and get proper sensor and take my computer to see if they can tune it to turn off dod.
 
Your original post referred to "miss fire P0300 Lean/Rich issues.
I wish that I had not mention the DoD system. Do not let that influence your search
for the problem. If you have access to a scanner and could read some of the siginals
that the computer (PCM) is seeing, that would be of help trying to diagnosis the problem.
Examples: O2 sensors (there are 4 on a V8, two upstream and two downstream of the
cat converter. STFT (Short Term Fuel Trim) and LTFT (Long Term Fuel Trim).
MAS (Mass Air Flow Sensor) I hope others will offer more examples.
 
Before I ship the computer off I'm going to replace the o2 censors to be sure... Thanks a bunch! It is weird that I have these problems but can shut engine off and restart and everything is fine momentarily? I was just thinking that this dod could be engaging? Thanks again
 
Do you have access to a scanner that can read the OBD2 signals, and record freeze frames?
We are flying blind without knowing what the brain (PCM) is seeing.
 
Do you have a android phone? If so look at the threads that talk about Torque app
and bluetooth adapter. This would be a scanner app for the OB2.
 
I really dont think your dod has anything to do with this, but you can check this by unplugging the brake booster pressure sending unit. With this unplugged, the ecm will not try to engage dod. You will have a check engine light and a brake light, but other then that, you will be able to rule out the dod. But like I said, I dont think thats the problem. When you start it, does it fire right up, or does it crank for a few seconds?
 
Look on the passenger side of the power brake booster. Its the only thing plugged in there, sensor wise.
 
Look on the passenger side of the power brake booster. Its the only thing plugged in there, sensor wise.
 
Got it thank you and well...that is not the problem! Well I'm glad I didn't ship this off to be tuned. I'm gonna start back at square one and just retrace all my troubleshooting steps. Then I'll start buying sensors and so on if need be? Thanks for your help you saved me quite a bit of money and for that I am greatful!!!!
 
No problem, glad I could help. Another question for you. Was the motor you dropped in an LH6, the same as the the one you pulled out? And if so, what did it come out of? The reason I ask is that there are some differences between the LH6s in 06 depending on what they came out of.
 
The motor came out of another 06 Denali envoy. Both were 5.3 and I actually used the wiring harness that came with it so everything matched up perfectly. So yes same vehicle year and all....
 
Did you use the coil packs that came with the replacement motor, or your original coils? And I wouldnt start buying new sensors, you have a second set of everything on your original motor, including coil packs.
 
I originally used new motor coils but have swapped out for originals after issues. Off the old motor I have used coil packs, throttle body and injectors, camshaft sensor, and plug wires. Installed new iridium plugs and an aftermarket coolant temp sensor all of which made no changes in problem. At this point I'm thinking about putting in all new o2 sensors? However those were fine prior to motor swap? Do you think I should swap new wiring harness for original on? I've been thinking about that at this point but any input helps? Thanks again
 
for the time being if I were you I would first change the temp sensor to an OEM AcDelco/GM unit, then go from there....
 
You've checked your manifolds for damage? You could also spray some .... anyone know what he could spray around the intake to check for leaks...not sure it's a good idea to spray throttle body cleaner around coils...:D
 
I know this is a long shot but is it possible that the wheel that the cam sensor reads has a different amount of gaps than old engine? Thus causing the misfires? I think it's called the reluctor wheel? Just a thought although they are same year. Is that a possibility? Thanks all
 
Ha probably the same number of teeth but may need to be re-synced! I did not even think of that til you mentioned the teeth. Gm or someone with a capable scanner can do it or hptuners.
 
Well, computers are off for a makeover.... No more DOD and a complete makeover. I will let you all know outcome soon?? Fingers crossed!!!
 
You will still have to do a case relearn once you get it back. I don't know why I didn't think of that. But you have to have the computer plugged into the engine and it basically syncs the crank and cam position sensors.
 
Thanks for info but I'll cross that bridge when it gets back. Is that gonna be a dealer thing to deal with?
 
A case relean, or crank sensor angle relearn, needs to be done when ever the crank sensor is changed. Do to small variances in the manufacturing of the reluctor wheel and crank sensor, when either is changed, the ecm/pcm needs to be "taught" the way the new sensor sees the reluctor wheel. After talking with a friend of mine about your symptoms, he says what your describing can be caused by needing a case relearn. Wish I got to you before you sent the ecm out. And no, not really a dealer thing, just need to find someone with a tech 2 scanner or snap on sonas. There is a way to do it without a scan tool, but I cant recall exactly what is involved.
 
That or Hptuners. It has the ability, too....dealer is probably cheaper, haha, but the dealer does not let you tune your car.
 
in addition to the dealer (tech2) and hpt, you can also use an msd dashhawk or an aeroforce interceptor.
 
Well gentleman I figured out misfire issue finally after wasting many hard earned dollars.......I had the two front oxygen sensors mixed up. Too bad the plugs were identical so I only had a 50/50 chance of getting it right! Anyway thank you to all for your input and help along the way! I appreciated it all, Jeff
 
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